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Cissé OH, Ma L, Kovacs JA. Retracing the evolution of Pneumocystis species, with a focus on the human pathogen Pneumocystis jirovecii. Microbiol Mol Biol Rev 2024; 88:e0020222. [PMID: 38587383 DOI: 10.1128/mmbr.00202-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024] Open
Abstract
SUMMARYEvery human being is presumed to be infected by the fungus Pneumocystis jirovecii at least once in his or her lifetime. This fungus belongs to a large group of species that appear to exclusively infect mammals, with P. jirovecii being the only one known to cause disease in humans. The mystery of P. jirovecii origin and speciation is just beginning to unravel. Here, we provide a review of the major steps of P. jirovecii evolution. The Pneumocystis genus likely originated from soil or plant-associated organisms during the period of Cretaceous ~165 million years ago and successfully shifted to mammals. The transition coincided with a substantial loss of genes, many of which are related to the synthesis of nutrients that can be scavenged from hosts or cell wall components that could be targeted by the mammalian immune system. Following the transition, the Pneumocystis genus cospeciated with mammals. Each species specialized at infecting its own host. Host specialization is presumably built at least partially upon surface glycoproteins, whose protogene was acquired prior to the genus formation. P. jirovecii appeared at ~65 million years ago, overlapping with the emergence of the first primates. P. jirovecii and its sister species P. macacae, which infects macaques nowadays, may have had overlapping host ranges in the distant past. Clues from molecular clocks suggest that P. jirovecii did not cospeciate with humans. Molecular evidence suggests that Pneumocystis speciation involved chromosomal rearrangements and the mounting of genetic barriers that inhibit gene flow among species.
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Affiliation(s)
- Ousmane H Cissé
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Liang Ma
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland, USA
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Apostolopoulou A, Fishman JA. The Pathogenesis and Diagnosis of Pneumocystis jiroveci Pneumonia. J Fungi (Basel) 2022; 8:1167. [PMID: 36354934 PMCID: PMC9696632 DOI: 10.3390/jof8111167] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 07/29/2023] Open
Abstract
Pneumocystis jiroveci remains an important fungal pathogen in immunocompromised hosts. The environmental reservoir remains unknown. Pneumonia (PJP) results from airborne transmission, including in nosocomial clusters, or with reactivation after an inadequately treated infection. Pneumocystis pneumonia most often occurs within 6 months of organ transplantation, with intensified or prolonged immunosuppression, notably with corticosteroids and following cytomegalovirus (CMV) infections. Infection may be recognized during recovery from neutropenia and lymphopenia. Invasive procedures may be required for early diagnosis and therapy. Despite being a well-established entity, aspects of the pathogenesis of PJP remain poorly understood. The goal of this review is to summarize the data on the pathogenesis of PJP, review the strengths and weaknesses of the pertinent diagnostic modalities, and discuss areas for future research.
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Affiliation(s)
- Anna Apostolopoulou
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Jay A. Fishman
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
- MGH Transplant Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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Kim HS, Nam HW, Ahn HJ, Lee SH, Kim YH. Spatiotemporal Clusters and Trends of Pneumocystis Pneumonia in Korea. THE KOREAN JOURNAL OF PARASITOLOGY 2022; 60:327-338. [DOI: 10.3347/kjp.2022.60.5.327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 09/04/2022] [Indexed: 11/06/2022]
Abstract
This study determined the recent status and trend of <i>Pneumocystis jirovecii</i> pneumonia (PcP) in the non-human immunodeficiency virus (HIV) (non-HIV-PcP) and HIV (HIV-PcP) infected populations using data from the Health Insurance Review & Assessment Service (HIRA) and the Korea Disease Control and Prevention Agency (KDCA). SaTScan and Joinpoint were used for statistical analyses. Non-HIV-PcP cases showed an upward trend during the study period from 2010 to 2021, with the largest number in 2021 (551 cases). The upward trend was similar until 2020 after adjusting for the population. Seoul had the highest number of cases (1,597) in the non-HIV-PcP group, which was the same after adjusting for the population (162 cases/1,000,000). It was followed by Jeju-do (89 cases/1,000,000). The most likely cluster (MLC) for the non-HIV-PCP group was Seoul (Relative Risk (RR)=4.59, Log Likelihood Ratio (LLR)=825.531), followed by Jeju-do (RR=1.59, LLR=5.431). An upward trend was observed among the non-HIV-PcP group in the Jeju-do/Jeollanam-do/Jeollabuk-do/Gyeongsangnam-do/Busan/Daejeon/Daegu/Ulsan joint cluster (29.02%, LLR=11.638, <i>P</i><0.001) located in the southern part of Korea. Both women and men in the non-HIV groups showed an overall upward trend of PcP during the study period. Men in the 60-69 age group had the highest annual percentage change (APC 41.8) during 2014-2019. In contrast, the HIV groups showed a falling trend of PcP recently. Men in the 60-69 age group had the most decrease (APC -17.6) during 2018-2021. This study provides an analytic basis for health measures and a nationwide epidemiological surveillance system for the management of PcP.
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Chesnay A, Paget C, Heuzé-Vourc’h N, Baranek T, Desoubeaux G. Pneumocystis Pneumonia: Pitfalls and Hindrances to Establishing a Reliable Animal Model. J Fungi (Basel) 2022; 8:jof8020129. [PMID: 35205883 PMCID: PMC8877242 DOI: 10.3390/jof8020129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/20/2022] [Accepted: 01/26/2022] [Indexed: 02/06/2023] Open
Abstract
Pneumocystis pneumonia is a severe lung infection that occurs primarily in largely immunocompromised patients. Few treatment options exist, and the mortality rate remains substantial. To develop new strategies in the fields of diagnosis and treatment, it appears to be critical to improve the scientific knowledge about the biology of the Pneumocystis agent and the course of the disease. In the absence of in vitro continuous culture system, in vivo animal studies represent a crucial cornerstone for addressing Pneumocystis pneumonia in laboratories. Here, we provide an overview of the animal models of Pneumocystis pneumonia that were reported in the literature over the last 60 years. Overall, this review highlights the great heterogeneity of the variables studied: the choice of the host species and its genetics, the different immunosuppressive regimens to render an animal susceptible, the experimental challenge, and the different validation methods of the model. With this work, the investigator will have the keys to choose pivotal experimental parameters and major technical features that are assumed to likely influence the results according to the question asked. As an example, we propose an animal model to explore the immune response during Pneumocystis pneumonia.
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Affiliation(s)
- Adélaïde Chesnay
- Service de Parasitologie-Mycologie-Médecine Tropicale, Pôle Biologie Médicale, Hôpital Bretonneau, CHRU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France;
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
- Correspondence:
| | - Christophe Paget
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
| | - Nathalie Heuzé-Vourc’h
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
| | - Thomas Baranek
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
| | - Guillaume Desoubeaux
- Service de Parasitologie-Mycologie-Médecine Tropicale, Pôle Biologie Médicale, Hôpital Bretonneau, CHRU de Tours, 2 Boulevard Tonnellé, 37044 Tours, France;
- Centre d’Etude des Pathologies Respiratoires (CEPR), Institut National de la Santé et de la Recherche Médicale U1100, Université de Tours, 10 Bouelvard Tonnellé, 37032 Tours, France; (C.P.); (N.H.-V.); (T.B.)
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Giannoulopoulos G, Lobetti R. Pneumocystosis in a lurcher puppy. Med Mycol Case Rep 2020; 30:15-18. [PMID: 33014701 PMCID: PMC7522037 DOI: 10.1016/j.mmcr.2020.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/07/2020] [Accepted: 09/15/2020] [Indexed: 11/28/2022] Open
Abstract
A 10-month-old lurcher with history of recurrent skin problems, presented with tachypnoea which had progressively become severe. Investigations included haematology, serum biochemistry, blood coagulation profile, diagnostic imaging, bronchoscopy and bronchoalveolar lavage (BAL). Cytological evaluation of the BAL revealed the presence of Pneumocystis cysts. The patient was euthanased on humane grounds prior to treatment against Pneumocystosis. To the best of our knowledge this is the first case of Pneumocystosis in a lurcher puppy.
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Affiliation(s)
- George Giannoulopoulos
- Wilson Veterinary Group, 5-11 Tenters Street, Bishop Auckland, County Durham, United Kingdom
| | - Remo Lobetti
- Bryanston Veterinary Hospital, 6 Ballyclare Drive, Bryanston, Johannesburg, South Africa
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Abstract
Environmental exposure has a significant impact on human health. While some airborne fungi can cause life-threatening infections, the impact of environment on fungal spore dispersal and transmission is poorly understood. The democratization of shotgun metagenomics allows us to explore important questions about fungal propagation. We focus on Pneumocystis, a genus of host-specific fungi that infect mammals via airborne particles. In humans, Pneumocystis jirovecii causes lethal infections in immunocompromised patients if untreated, although its environmental reservoir and transmission route remain unclear. Environmental exposure has a significant impact on human health. While some airborne fungi can cause life-threatening infections, the impact of environment on fungal spore dispersal and transmission is poorly understood. The democratization of shotgun metagenomics allows us to explore important questions about fungal propagation. We focus on Pneumocystis, a genus of host-specific fungi that infect mammals via airborne particles. In humans, Pneumocystis jirovecii causes lethal infections in immunocompromised patients if untreated, although its environmental reservoir and transmission route remain unclear. Here, we attempt to clarify, by analyzing human exposome metagenomic data sets, whether humans are exposed to different Pneumocystis species present in the air but only P. jirovecii cells are able to replicate or whether they are selectively exposed to P. jirovecii. Our analysis supports the latter hypothesis, which is consistent with a local transmission model. These data also suggest that healthy carriers are a major driver for the transmission.
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Dellière S, Gits-Muselli M, Bretagne S, Alanio A. Outbreak-Causing Fungi: Pneumocystis jirovecii. Mycopathologia 2019; 185:783-800. [PMID: 31782069 DOI: 10.1007/s11046-019-00408-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/15/2019] [Indexed: 12/17/2022]
Abstract
Pneumocystis jirovecii pneumonia (PCP) is an important cause of morbidity in immunocompromised patients, with a higher mortality in non-HIV than in HIV patients. P. jirovecii is one of the rare transmissible pathogenic fungi and the only one that depends fully on the host to survive and proliferate. Transmissibility among humans is one of the main specificities of P. jirovecii. Hence, the description of multiple outbreaks raises questions regarding preventive care management of the disease, especially in the non-HIV population. Indeed, chemoprophylaxis is well codified in HIV patients but there is a trend for modifications of the recommendations in the non-HIV population. In this review, we aim to discuss the mode of transmission of P. jirovecii, identify published outbreaks of PCP and describe molecular tools available to study these outbreaks. Finally, we discuss public health and infection control implications of PCP outbreaks in hospital setting for in- and outpatients.
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Affiliation(s)
- Sarah Dellière
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université de Paris, Paris, France
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France
| | - Maud Gits-Muselli
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université de Paris, Paris, France
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université de Paris, Paris, France
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France
- National Reference Center for Invasive Mycoses and Antifungals (NRCMA), Institut Pasteur, Paris, France
| | - Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université de Paris, Paris, France.
- Molecular Mycology Unit, CNRS UMR2000, Institut Pasteur, 25 rue du Dr Roux, 75724, Paris Cedex 15, France.
- National Reference Center for Invasive Mycoses and Antifungals (NRCMA), Institut Pasteur, Paris, France.
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Transcriptomic and Proteomic Approaches to Finding Novel Diagnostic and Immunogenic Candidates in Pneumocystis. mSphere 2019; 4:4/5/e00488-19. [PMID: 31484742 PMCID: PMC6731532 DOI: 10.1128/msphere.00488-19] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Pneumocystis pneumonia is the most common serious opportunistic infection in patients with HIV/AIDS. Furthermore, Pneumocystis pneumonia is a feared complication of the immunosuppressive drug regimens used to treat autoimmunity, malignancy, and posttransplantation rejection. With an increasing at-risk population, there is a strong need for novel approaches to discover diagnostic and vaccine targets. There are multiple challenges to finding these targets, however. First, Pneumocystis has a largely unannotated genome. To address this, we evaluated each protein encoded within the Pneumocystis genome by comparisons to proteins encoded within the genomes of other fungi using NCBI BLAST. Second, Pneumocystis relies on a multiphasic life cycle, as both the transmissible form (the ascus) and the replicative form (the trophozoite [troph]) reside within the alveolar space of the host. To that end, we purified asci and trophs from Pneumocystis murina and utilized transcriptomics to identify differentially regulated genes. Two such genes, Arp9 and Sp, are differentially regulated in the ascus and the troph, respectively, and can be utilized to characterize the state of the Pneumocystis life cycle in vivo Gsc1, encoding a β-1,3-glucan synthase with a large extracellular domain previously identified using surface proteomics, was more highly expressed on the ascus form of Pneumocystis GSC-1 ectodomain immunization generated a strong antibody response that demonstrated the ability to recognize the surface of the Pneumocystis asci. GSC-1 ectodomain immunization was also capable of reducing ascus burden following primary challenge with Pneumocystis murina Finally, mice immunized with the GSC-1 ectodomain had limited fungal burden following natural transmission of Pneumocystis using a cohousing model.IMPORTANCE The current report enhances our understanding of Pneumocystis biology in a number of ways. First, the current study provided a preliminary annotation of the Pneumocystis murina genome, addressing a long-standing issue in the field. Second, this study validated two novel transcripts enriched in the two predominant life forms of Pneumocystis These findings allow better characterization of the Pneumocystis life cycle in vivo and could be valuable diagnostic tools. Furthermore, this study outlined a novel pipeline of -omics techniques capable of revealing novel antigens (e.g., GSC-1) for the development of vaccines against Pneumocystis.
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Bhagwat SP, Gigliotti F, Wang J, Wang Z, Notter RH, Murphy PS, Rivera-Escalera F, Malone J, Jordan MB, Elliott MR, Wright TW. Intrinsic Programming of Alveolar Macrophages for Protective Antifungal Innate Immunity Against Pneumocystis Infection. Front Immunol 2018; 9:2131. [PMID: 30283457 PMCID: PMC6156154 DOI: 10.3389/fimmu.2018.02131] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 08/29/2018] [Indexed: 11/25/2022] Open
Abstract
Invasive fungal infections, including Pneumocystis Pneumonia (PcP), remain frequent life-threatening conditions of patients with adaptive immune defects. While innate immunity helps control pathogen growth early during infection, it is typically not sufficient for complete protection against Pneumocystis and other human fungal pathogens. Alveolar macrophages (AM) possess pattern recognition molecules capable of recognizing antigenic and structural determinants of Pneumocystis. However, this pathogen effectively evades innate immunity to infect both immunocompetent and immunosuppressed hosts, albeit with differing outcomes. During our studies of mouse models of PcP, the FVB/N strain was identified as unique because of its ability to mount a protective innate immune response against Pneumocystis infection. In contrast to other immunocompetent strains, which become transiently infected prior to the onset of adaptive immunity, FVB/N mice rapidly eradicated Pneumocystis before an adaptive immune response was triggered. Furthermore, FVB/N mice remained highly resistant to infection even in the absence of functional T cells. The effector mechanism of innate protection required the action of functional alveolar macrophages, and the adoptive transfer of resistant FVB/N AMs, but not susceptible CB.17 AMs, conferred protection to immunodeficient mice. Macrophage IFNγ receptor signaling was not required for innate resistance, and FVB/N macrophages were found to display markers of alternative activation. IFNγ reprogrammed resistant FVB/N macrophages to a permissive M1 biased phenotype through a mechanism that required direct activation of the macrophage IFNγR. These results demonstrate that appropriately programmed macrophages provide protective innate immunity against this opportunistic fungal pathogen, and suggest that modulating macrophage function may represent a feasible therapeutic strategy to enhance antifungal host defense. The identification of resistant and susceptible macrophages provides a novel platform to study not only the mechanisms of macrophage-mediated antifungal defense, but also the mechanisms by which Pneumocystis evades innate immunity.
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Affiliation(s)
- Samir P. Bhagwat
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Francis Gigliotti
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Jing Wang
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Zhengdong Wang
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Robert H. Notter
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Patrick S. Murphy
- David H. Smith Center for Vaccine Biology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Fátima Rivera-Escalera
- David H. Smith Center for Vaccine Biology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Jane Malone
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Michael B. Jordan
- Divisions of Immunobiology, and Bone Marrow Transplantation and Immune Deficiency, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Michael R. Elliott
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
- David H. Smith Center for Vaccine Biology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Terry W. Wright
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
- Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
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Ma L, Cissé OH, Kovacs JA. A Molecular Window into the Biology and Epidemiology of Pneumocystis spp. Clin Microbiol Rev 2018; 31:e00009-18. [PMID: 29899010 PMCID: PMC6056843 DOI: 10.1128/cmr.00009-18] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pneumocystis, a unique atypical fungus with an elusive lifestyle, has had an important medical history. It came to prominence as an opportunistic pathogen that not only can cause life-threatening pneumonia in patients with HIV infection and other immunodeficiencies but also can colonize the lungs of healthy individuals from a very early age. The genus Pneumocystis includes a group of closely related but heterogeneous organisms that have a worldwide distribution, have been detected in multiple mammalian species, are highly host species specific, inhabit the lungs almost exclusively, and have never convincingly been cultured in vitro, making Pneumocystis a fascinating but difficult-to-study organism. Improved molecular biologic methodologies have opened a new window into the biology and epidemiology of Pneumocystis. Advances include an improved taxonomic classification, identification of an extremely reduced genome and concomitant inability to metabolize and grow independent of the host lungs, insights into its transmission mode, recognition of its widespread colonization in both immunocompetent and immunodeficient hosts, and utilization of strain variation to study drug resistance, epidemiology, and outbreaks of infection among transplant patients. This review summarizes these advances and also identifies some major questions and challenges that need to be addressed to better understand Pneumocystis biology and its relevance to clinical care.
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Affiliation(s)
- Liang Ma
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, Maryland, USA
| | - Ousmane H Cissé
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, Maryland, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, Bethesda, Maryland, USA
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11
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Investigating Clinical Issues by Genotyping of Medically Important Fungi: Why and How? Clin Microbiol Rev 2017; 30:671-707. [PMID: 28490578 DOI: 10.1128/cmr.00043-16] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Genotyping studies of medically important fungi have addressed elucidation of outbreaks, nosocomial transmissions, infection routes, and genotype-phenotype correlations, of which secondary resistance has been most intensively investigated. Two methods have emerged because of their high discriminatory power and reproducibility: multilocus sequence typing (MLST) and microsatellite length polymorphism (MLP) using short tandem repeat (STR) markers. MLST relies on single-nucleotide polymorphisms within the coding regions of housekeeping genes. STR polymorphisms are based on the number of repeats of short DNA fragments, mostly outside coding regions, and thus are expected to be more polymorphic and more rapidly evolving than MLST markers. There is no consensus on a universal typing system. Either one or both of these approaches are now available for Candida spp., Aspergillus spp., Fusarium spp., Scedosporium spp., Cryptococcus neoformans, Pneumocystis jirovecii, and endemic mycoses. The choice of the method and the number of loci to be tested depend on the clinical question being addressed. Next-generation sequencing is becoming the most appropriate method for fungi with no MLP or MLST typing available. Whatever the molecular tool used, collection of clinical data (e.g., time of hospitalization and sharing of similar rooms) is mandatory for investigating outbreaks and nosocomial transmission.
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12
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Nevez G, Le Gal S, Noel N, Wynckel A, Huguenin A, Le Govic Y, Pougnet L, Virmaux M, Toubas D, Bajolet O. Investigation of nosocomial pneumocystis infections: usefulness of longitudinal screening of epidemic and post-epidemic pneumocystis genotypes. J Hosp Infect 2017; 99:332-345. [PMID: 28943270 DOI: 10.1016/j.jhin.2017.09.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/18/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Twenty-five patients, of whom 22 were renal transplant recipients, developed Pneumocystis jirovecii infections at the nephrology department of Reims University Hospital (France) from September 2008 to October 2009, whereas only four sporadic cases had been diagnosed in this department over the 14 previous years. AIM This outbreak was investigated by analysing patient encounters and P. jirovecii types. METHODS A transmission map was drawn up. P. jirovecii typing at DHPS, ITS and mtLSU rRNA sequences was performed in the patients of the cluster (18 patients with Pneumocystis pneumonia (PCP) and seven colonized patients), 10 unlinked control patients (six PCP patients and four colonized patients), as well as 23 other patients diagnosed with P. jirovecii (nine PCP patients and 14 colonized patients) in the same department over a three-year post-epidemic period. FINDINGS Eleven encounters between patients harbouring the same types were observed. Three PCP patients and one colonized patient were considered as possible index cases. The most frequent types in the cluster group and the control group were identical. However, their frequency was significantly higher in the first than in the second group (P < 0.01). Identical types were also identified in the post-epidemic group, suggesting a second outbreak due to the same strain, contemporary to a disruption in prevention measures. CONCLUSIONS These results provide additional data on the role of both PCP and colonized patients as infectious sources. Longitudinal screening of P. jirovecii types in infected patients, including colonized patients, is required in the investigation of the fungus's circulation within hospitals.
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Affiliation(s)
- G Nevez
- Université de Bretagne Loire, GEIHP EA 3142, Brest, France; Laboratory of Parasitology and Mycology, Brest University Hospital, Brest, France.
| | - S Le Gal
- Université de Bretagne Loire, GEIHP EA 3142, Brest, France; Laboratory of Parasitology and Mycology, Brest University Hospital, Brest, France
| | - N Noel
- Department of Nephrology, Reims University Hospital, Reims, France
| | - A Wynckel
- Department of Nephrology, Reims University Hospital, Reims, France
| | - A Huguenin
- Laboratory of Parasitology and Mycology, Reims University Hospital, Reims, France
| | - Y Le Govic
- Université de Bretagne Loire, GEIHP EA 3142, Angers, France
| | - L Pougnet
- Université de Bretagne Loire, GEIHP EA 3142, Brest, France
| | - M Virmaux
- Université de Bretagne Loire, GEIHP EA 3142, Brest, France
| | - D Toubas
- Laboratory of Parasitology and Mycology, Reims University Hospital, Reims, France; Université de Reims Champagne-Ardenne, Equipe MéDIAN, Biophotonique et Technologies pour la Santé, Reims, France
| | - O Bajolet
- Université de Reims Champagne-Ardenne, EA 7887, Reims, France; Equipe Opérationnelle d'Hygiène, Reims University Hospital, Reims, France
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Abstract
Pneumocystis jirovecii is an unusual ascomycetous fungus that can be detected in the lungs of healthy individuals. Transmission from human to human is one of its main characteristics in comparison with other fungi responsible for invasive infections.
P. jirovecii is transmitted through the air between healthy individuals, who are considered to be the natural reservoir, at least transiently. In immunocompromised patients,
P. jirovecii multiplies, leading to subacute infections and acute life-threatening pneumonia, called Pneumocystis pneumonia [PCP]. PCP is caused by genotypically distinct mixtures of organisms in more than 90% of cases, reinforcing the hypothesis that there is constant inhalation of
P. jirovecii from different contacts over time, although reactivation of latent organisms from previous exposures may be possible. Detection of
P. jirovecii DNA without any symptoms or related radiological signs has been called “colonization”. This situation could be considered as the result of recent exposure to
P. jirovecii that could evolve towards PCP, raising the issue of cotrimoxazole prophylaxis for at-risk quantitative polymerase chain reaction (qPCR)-positive immunocompromised patients. The more accurate way to diagnose PCP is the use of real-time quantitative PCR, which prevents amplicon contamination and allows determination of the fungal load that is mandatory to interpret the qPCR results and manage the patient appropriately. The detection of
P. jirovecii in respiratory samples of immunocompromised patients should be considered for potential risk of developing PCP. Many challenges still need to be addressed, including a better description of transmission, characterization of organisms present at low level, and prevention of environmental exposure during immunodepression.
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Affiliation(s)
- Alexandre Alanio
- Parasitology-Mycology Laboratory, Lariboisière Saint-Louis Fernand Widal Hospitals, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris-Diderot, Sorbonne Paris Cité University, Paris, France.,Molecular Mycology Unit, CNRS, Institut Pasteur, URA 3012, Paris, France
| | - Stéphane Bretagne
- Parasitology-Mycology Laboratory, Lariboisière Saint-Louis Fernand Widal Hospitals, Assistance Publique-Hôpitaux de Paris, Paris, France.,Paris-Diderot, Sorbonne Paris Cité University, Paris, France.,Molecular Mycology Unit, CNRS, Institut Pasteur, URA 3012, Paris, France
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Immunization with Pneumocystis Cross-Reactive Antigen 1 (Pca1) Protects Mice against Pneumocystis Pneumonia and Generates Antibody to Pneumocystis jirovecii. Infect Immun 2017; 85:IAI.00850-16. [PMID: 28031260 DOI: 10.1128/iai.00850-16] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 12/19/2016] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis pneumonia (PcP) is a life-threatening infection that affects immunocompromised individuals. Nearly half of all PcP cases occur in those prescribed effective chemoprophylaxis, suggesting that additional preventive methods are needed. To this end, we have identified a unique mouse Pneumocystis surface protein, designated Pneumocystis cross-reactive antigen 1 (Pca1), as a potential vaccine candidate. Mice were immunized with a recombinant fusion protein containing Pca1. Subsequently, CD4+ T cells were depleted, and the mice were exposed to Pneumocystis murina Pca1 immunization completely protected nearly all mice, similar to immunization with whole Pneumocystis organisms. In contrast, all immunized negative-control mice developed PcP. Unexpectedly, Pca1 immunization generated cross-reactive antibody that recognized Pneumocystis jirovecii and Pneumocystis carinii Potential orthologs of Pca1 have been identified in P. jirovecii Such cross-reactivity is rare, and our findings suggest that Pca1 is a conserved antigen and potential vaccine target. The evaluation of Pca1-elicited antibodies in the prevention of PcP in humans deserves further investigation.
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Alanio A, Gits-Muselli M, Mercier-Delarue S, Dromer F, Bretagne S. Diversity of Pneumocystis jirovecii during Infection Revealed by Ultra-Deep Pyrosequencing. Front Microbiol 2016; 7:733. [PMID: 27252684 PMCID: PMC4877386 DOI: 10.3389/fmicb.2016.00733] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/02/2016] [Indexed: 01/05/2023] Open
Abstract
Pneumocystis jirovecii is an uncultivable fungal pathogen responsible for Pneumocystis pneumonia (PCP) in immunocompromised patients, the physiopathology of which is only partially understood. The diversity of the Pneumocystis strains associated with acute infection has mainly been studied by Sanger sequencing techniques precluding any identification of rare genetic events (< 20% frequency). We used next-generation sequencing to detect minority variants causing infection, and analyzed the complexity of the genomes of infection-causing P. jirovecii. Ultra-deep pyrosequencing (UDPS) of PCR amplicons of two nuclear target region [internal transcribed spacer 2 (ITS2) and dihydrofolate reductase (DHFR)] and one mitochondrial DNA target region [the mitochondrial ribosomal RNA large subunit gene (mtLSU)] was performed on 31 samples from 25 patients. UDPS revealed that almost all patients (n = 23/25, 92%) were infected with mixtures of strains. An analysis of repeated samples from six patients showed that the proportion of each variant change significantly (by up to 30%) over time on treatment in three of these patients. A comparison of mitochondrial and nuclear UDPS data revealed heteroplasmy in P. jirovecii. The recognition site for the homing endonuclease I-SceI was recovered from the mtLSU gene, whereas its two conserved motifs of the enzyme were not. This suggests that heteroplasmy may result from recombination induced by unidentified homing endonucleases. This study sheds new light on the biology of P. jirovecii during infection. PCP results from infection not with a single microorganism, but with a complex mixture of different genotypes, the proportions of which change over time due to intricate selection and reinfection mechanisms that may differ between patients, treatments, and predisposing diseases.
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Affiliation(s)
- Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-LouisParis, France; Université Paris Diderot, Sorbonne Paris CitéParis, France; Unité de Mycologie Moléculaire, Département de Mycologie, Centre National de Référence Mycoses Invasives et Antifongiques, Institut PasteurParis, France; Centre National de la Recherche Scientifique CNRS URA3012Paris, France
| | - Maud Gits-Muselli
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-LouisParis, France; Université Paris Diderot, Sorbonne Paris CitéParis, France
| | - Séverine Mercier-Delarue
- Laboratoire de Microbiologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-Louis Paris, France
| | - Françoise Dromer
- Unité de Mycologie Moléculaire, Département de Mycologie, Centre National de Référence Mycoses Invasives et Antifongiques, Institut PasteurParis, France; Centre National de la Recherche Scientifique CNRS URA3012Paris, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Assistance Publique Hôpitaux de Paris, Hôpital Saint-LouisParis, France; Université Paris Diderot, Sorbonne Paris CitéParis, France; Unité de Mycologie Moléculaire, Département de Mycologie, Centre National de Référence Mycoses Invasives et Antifongiques, Institut PasteurParis, France; Centre National de la Recherche Scientifique CNRS URA3012Paris, France
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Alanio A, Hauser PM, Lagrou K, Melchers WJG, Helweg-Larsen J, Matos O, Cesaro S, Maschmeyer G, Einsele H, Donnelly JP, Cordonnier C, Maertens J, Bretagne S. ECIL guidelines for the diagnosis of Pneumocystis jirovecii pneumonia in patients with haematological malignancies and stem cell transplant recipients. J Antimicrob Chemother 2016; 71:2386-96. [PMID: 27550991 DOI: 10.1093/jac/dkw156] [Citation(s) in RCA: 165] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The Fifth European Conference on Infections in Leukaemia (ECIL-5) convened a meeting to establish evidence-based recommendations for using tests to diagnose Pneumocystis jirovecii pneumonia (PCP) in adult patients with haematological malignancies. Immunofluorescence assays are recommended as the most sensitive microscopic method (recommendation A-II: ). Real-time PCR is recommended for the routine diagnosis of PCP ( A-II: ). Bronchoalveolar lavage (BAL) fluid is recommended as the best specimen as it yields good negative predictive value ( A-II: ). Non-invasive specimens can be suitable alternatives ( B-II: ), acknowledging that PCP cannot be ruled out in case of a negative PCR result ( A-II: ). Detecting β-d-glucan in serum can contribute to the diagnosis but not the follow-up of PCP ( A-II: ). A negative serum β-d-glucan result can exclude PCP in a patient at risk ( A-II: ), whereas a positive test result may indicate other fungal infections. Genotyping using multilocus sequence markers can be used to investigate suspected outbreaks ( A-II: ). The routine detection of dihydropteroate synthase mutations in cases of treatment failure is not recommended ( B-II: ) since these mutations do not affect response to high-dose co-trimoxazole. The clinical utility of these diagnostic tests for the early management of PCP should be further assessed in prospective, randomized interventional studies.
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Affiliation(s)
- Alexandre Alanio
- Parasitology-Mycology Laboratory, Groupe Hospitalier Lariboisière Saint-Louis Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université Paris-Diderot, Sorbonne Paris Cité, and Institut Pasteur, Unité de Mycologie Moléculaire, CNRS URA3012, Centre National de Référence Mycoses Invasives et Antifongiques, Paris, France
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Katrien Lagrou
- Department of Microbiology and Immunology, Catholic University Leuven, Leuven, Belgium and National Reference Center for Mycosis, Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium
| | - Willem J G Melchers
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jannik Helweg-Larsen
- Department of Infectious Diseases, Rigshospitalet-Copenhagen University Hospital, Copenhagen, Denmark
| | - Olga Matos
- Medical Parasitology Unit, Group of Opportunistic Protozoa/HIV and Other Protozoa, Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Portugal Universidade Nova de Lisboa, Lisboa, Portugal
| | - Simone Cesaro
- Hematology Department, Oncoematologia Pediatrica, Policlinico G. B. Rossi, Verona, Italy
| | - Georg Maschmeyer
- Department of Hematology, Oncology and Palliative Care, Ernst-von-Bergmann Klinikum, Potsdam, Germany
| | - Hermann Einsele
- Medizinische Klinik und Poliklinik II, Julius Maximilians Universitaet, Würzburg, Germany
| | - J Peter Donnelly
- Department of Hematology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Catherine Cordonnier
- Hematology Department, Henri Mondor Hospital, APHP and Université Paris-Est-Créteil, Créteil, France
| | - Johan Maertens
- Hematology Department, University Hospital Leuven, Campus Gasthuisberg, Leuven, Belgium
| | - Stéphane Bretagne
- Parasitology-Mycology Laboratory, Groupe Hospitalier Lariboisière Saint-Louis Fernand Widal, Assistance Publique-Hôpitaux de Paris (AP-HP), Université Paris-Diderot, Sorbonne Paris Cité, and Institut Pasteur, Unité de Mycologie Moléculaire, CNRS URA3012, Centre National de Référence Mycoses Invasives et Antifongiques, Paris, France
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Goto N, Futamura K, Okada M, Yamamoto T, Tsujita M, Hiramitsu T, Narumi S, Watarai Y. Management of Pneumocystis jirovecii Pneumonia in Kidney Transplantation to Prevent Further Outbreak. CLINICAL MEDICINE INSIGHTS-CIRCULATORY RESPIRATORY AND PULMONARY MEDICINE 2015; 9:81-90. [PMID: 26609250 PMCID: PMC4648609 DOI: 10.4137/ccrpm.s23317] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/11/2015] [Accepted: 08/12/2015] [Indexed: 12/19/2022]
Abstract
The outbreak of Pneumocystis jirovecii pneumonia (PJP) among kidney transplant recipients is emerging worldwide. It is important to control nosocomial PJP infection. A delay in diagnosis and treatment increases the number of reservoir patients and the number of cases of respiratory failure and death. Owing to the large number of kidney transplant recipients compared to other types of organ transplantation, there are greater opportunities for them to share the same time and space. Although the use of trimethoprim-sulfamethoxazole (TMP-SMX) as first choice in PJP prophylaxis is valuable for PJP that develops from infections by trophic forms, it cannot prevent or clear colonization, in which cysts are dominant. Colonization of P. jirovecii is cleared by macrophages. While recent immunosuppressive therapies have decreased the rate of rejection, over-suppressed macrophages caused by the higher levels of immunosuppression may decrease the eradication rate of colonization. Once a PJP cluster enters these populations, which are gathered in one place and uniformly undergoing immunosuppressive therapy for kidney transplantation, an outbreak can occur easily. Quick actions for PJP patients, other recipients, and medical staff of transplant centers are required. In future, lifelong prophylaxis may be required even in kidney transplant recipients.
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Affiliation(s)
- Norihiko Goto
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
| | - Kenta Futamura
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
| | - Manabu Okada
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
| | - Takayuki Yamamoto
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
| | - Makoto Tsujita
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
| | - Takahisa Hiramitsu
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
| | - Shunji Narumi
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
| | - Yoshihiko Watarai
- Department of Transplant Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan
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Bishop LR, Lionakis MS, Sassi M, Murphy PM, Hu X, Huang DW, Sherman B, Qiu J, Yang J, Lempicki RA, Kovacs JA. Characterization of chemokine and chemokine receptor expression during Pneumocystis infection in healthy and immunodeficient mice. Microbes Infect 2015; 17:638-50. [PMID: 26052064 PMCID: PMC4554965 DOI: 10.1016/j.micinf.2015.05.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 05/06/2015] [Accepted: 05/25/2015] [Indexed: 10/23/2022]
Abstract
We examined gene expression levels of multiple chemokines and chemokine receptors during Pneumocystis murina infection in wild-type and immunosuppressed mice, using microarrays and qPCR. In wild-type mice, expression of chemokines that are ligands for Ccr2, Cxcr3, Cxcr6, and Cxcr2 increased at days 32-41 post-infection, with a return to baseline by day 75-150. Concomitant increases were seen in Ccr2, Cxcr3, and Cxcr6, but not in Cxcr2 expression. Induction of these same factors also occurred in CD40-ligand and CD40 knockout mice but only at a much later time-point, during uncontrolled Pneumocystis pneumonia (PCP). Expression of CD4 Th1 markers was increased in wild-type mice during clearance of infection. Ccr2 and Cx3cr1 knockout mice cleared Pneumocystis infection with kinetics similar to wild-type mice, and all animals developed anti-Pneumocystis antibodies. Upregulation of Ccr2, Cxcr3, and Cxcr6 and their ligands supports an important role for T helper cells and mononuclear phagocytes in the clearance of Pneumocystis infection. However, based on the current and prior studies, no single chemokine receptor appears to be critical to the clearance of Pneumocystis.
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Affiliation(s)
- Lisa R Bishop
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Michail S Lionakis
- Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Monica Sassi
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Philip M Murphy
- Laboratory of Molecular Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xiaojun Hu
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Da Wei Huang
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Brad Sherman
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Ju Qiu
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Jun Yang
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Richard A Lempicki
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
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Pneumocystis jirovecii--from a commensal to pathogen: clinical and diagnostic review. Parasitol Res 2015; 114:3577-85. [PMID: 26281787 PMCID: PMC4562001 DOI: 10.1007/s00436-015-4678-6] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/07/2015] [Indexed: 01/09/2023]
Abstract
Pneumocystis pneumonia is an opportunistic disease caused by invasion of unicellular fungus Pneumocystis jirovecii. Initially, it was responsible for majority of morbidity and mortality cases among HIV-infected patients, which later have been reduced due to the introduction of anti-retroviral therapy, as well as anti-Pneumocystis prophylaxis among these patients. Pneumocystis pneumonia, however, is still a significant cause of mortality among HIV-negative patients being under immunosuppression caused by different factors, such as transplant recipients as well as oncologically treated ones. The issue of pneumocystosis among these people is particularly emphasized in the article, since rapid onset and fast progression of severe symptoms result in high mortality rate among these patients, who thereby represent the group of highest risk of developing Pneumocystis pneumonia. In contrast, fungal invasion in immunocompetent people usually leads to asymptomatic colonization, which frequent incidence among healthy infants has even suggested the possibility of its association with sudden unexpected infant death syndrome. In the face of emerging strains with different epidemiological profiles resulting from genetic diversity, including drug-resistant genotypes, the colonization phenomenon desires particular attention, discussed in this article. We also summarize specific and sensitive methods, required for detection of Pneumocystis invasion and for distinguish colonization from the disease.
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Abstract
The interaction between host immunity and infections in the context of a suppressed immune system presents an opportunity to study the interaction of colonization and infection with the development of acute and chronic pulmonary morbidity and mortality. This article summarizes presentations at the Pittsburgh International Lung Conference about comorbid consequences in two categories of immunosuppressed hosts: HIV-infected individuals and lung transplant recipients. Specifically, chronic obstructive pulmonary disease, pulmonary hypertension, and chronic lung rejection after transplant are three diseases that may be consequences of colonization or infection by viruses or fungi, whether HIV itself or the opportunistic infections Pneumocystis and cytomegalovirus. In the fourth section, we discuss unique aspects of infections after lung transplant as well as the battle against multidrug-resistant organisms in this population and theorize that the immunosuppressed population may provide a unique group of patients in which to study ways to overcome nosocomial pathogenic challenges. These host-pathogen interactions serve as models for developing new strategies to reduce acute and chronic morbidity due to colonization and subclinical infection, and potential therapeutic avenues, which are often overlooked in the clinical arena.
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Gits-Muselli M, Peraldi MN, de Castro N, Delcey V, Menotti J, Guigue N, Hamane S, Raffoux E, Bergeron A, Valade S, Molina JM, Bretagne S, Alanio A. New Short Tandem Repeat-Based Molecular Typing Method for Pneumocystis jirovecii Reveals Intrahospital Transmission between Patients from Different Wards. PLoS One 2015; 10:e0125763. [PMID: 25933203 PMCID: PMC4416908 DOI: 10.1371/journal.pone.0125763] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 03/26/2015] [Indexed: 12/26/2022] Open
Abstract
Pneumocystis pneumonia is a severe opportunistic infection in immunocompromised patients caused by the unusual fungus Pneumocystis jirovecii. Transmission is airborne, with both immunocompromised and immunocompetent individuals acting as a reservoir for the fungus. Numerous reports of outbreaks in renal transplant units demonstrate the need for valid genotyping methods to detect transmission of a given genotype. Here, we developed a short tandem repeat (STR)-based molecular typing method for P. jirovecii. We analyzed the P. jirovecii genome and selected six genomic STR markers located on different contigs of the genome. We then tested these markers in 106 P. jirovecii PCR-positive respiratory samples collected between October 2010 and November 2013 from 91 patients with various underlying medical conditions. Unique (one allele per marker) and multiple (more than one allele per marker) genotypes were observed in 34 (32%) and 72 (68%) samples, respectively. A genotype could be assigned to 55 samples (54 patients) and 61 different genotypes were identified in total with a discriminatory power of 0.992. Analysis of the allelic distribution of the six markers and minimum spanning tree analysis of the 61 genotypes identified a specific genotype (Gt21) in our hospital, which may have been transmitted between 10 patients including six renal transplant recipients. Our STR-based molecular typing method is a quick, cheap and reliable approach to genotype Pneumocystis jirovecii in hospital settings and is sensitive enough to detect minor genotypes, thus enabling the study of the transmission and pathophysiology of Pneumocystis pneumonia.
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Affiliation(s)
- Maud Gits-Muselli
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Marie-Noelle Peraldi
- Service de transplantation rénale, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
| | - Nathalie de Castro
- Service de Maladie Infectieuses et tropicales, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Véronique Delcey
- Service de Médecine interne, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Hôpital Lariboisière, Paris, France
| | - Jean Menotti
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycoses invasives et Antifongiques, Paris, France
- CNRS URA3012, Paris, France
| | - Nicolas Guigue
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
| | - Samia Hamane
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Emmanuel Raffoux
- Service d’Hématologie adulte, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Anne Bergeron
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Service de Pneumologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Sandrine Valade
- Service de Réanimation, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Jean-Michel Molina
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Service de Maladie Infectieuses et tropicales, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
| | - Stéphane Bretagne
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycoses invasives et Antifongiques, Paris, France
- CNRS URA3012, Paris, France
| | - Alexandre Alanio
- Laboratoire de Parasitologie-Mycologie, AP-HP, Groupe Hospitalier Saint-Louis-Lariboisière-Fernand-Widal, Paris, France
- Université Paris-Diderot, Sorbonne Cité, Paris, France
- Institut Pasteur, Unité de Mycologie Moléculaire, Centre National de Référence Mycoses invasives et Antifongiques, Paris, France
- CNRS URA3012, Paris, France
- * E-mail:
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Le Gal S, Pougnet L, Damiani C, Fréalle E, Guéguen P, Virmaux M, Ansart S, Jaffuel S, Couturaud F, Delluc A, Tonnelier JM, Castellant P, Le Meur Y, Le Floch G, Totet A, Menotti J, Nevez G. Pneumocystis jirovecii in the air surrounding patients with Pneumocystis pulmonary colonization. Diagn Microbiol Infect Dis 2015; 82:137-42. [PMID: 25801779 DOI: 10.1016/j.diagmicrobio.2015.01.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 01/09/2015] [Accepted: 01/11/2015] [Indexed: 12/23/2022]
Abstract
In this study, Pneumocystis jirovecii was detected and characterized in the air surrounding patients with Pneumocystis pulmonary colonization. Air samples were collected in the rooms of 10 colonized patients using Coriolis® μ air sampler at 1m and 5m from the patient's head. P. jirovecii DNA was amplified and genotyped in pulmonary and air samples at the mitochondrial large subunit ribosomal RNA gene. P. jirovecii DNA was detected in 5 of the 10 air samples collected at 1m and in 5 of the 10 other air samples collected at 5m. P. jirovecii genotyping was successful in 4 pairs or triplets of air and pulmonary samples. Full genotype matches were observed in 3 of the 4 pairs or triplets of air and pulmonary samples. These results provide original data supporting P. jirovecii exhalation from colonized patients and emphasize the risk of P. jirovecii nosocomial transmission from this patient population.
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Affiliation(s)
- Solène Le Gal
- University of Brest, LUBEM EA 3882, SFR 148, Brest, France; Laboratory of Parasitology and Mycology, Brest University Hospital, Brest, France.
| | - Laurence Pougnet
- Laboratory, Military Teaching Hospital Clermont Tonnerre, Brest, France
| | - Céline Damiani
- University of Picardy-Jules Verne, UMR-I 01, SFR Cap Santé, Amiens, France; Laboratory of Parasitology and Mycology, Amiens University Hospital, Amiens, France
| | - Emilie Fréalle
- Laboratory of Parasitology and Mycology, Lille University Hospital, Lille, France
| | - Paul Guéguen
- Laboratory of Molecular Genetics and Histocompatibility, Brest University Hospital, Brest, France; University of Brest, INSERM U1078, Molecular Genetics and Epidemiological Genetics, SFR 148, Brest, France
| | | | - Séverine Ansart
- Department of Infectious Diseases, Brest University Hospital, Brest, France; University of Brest, INSERM UMR 1101, Laboratory of Medical Information Processing, SFR 148, Brest, France
| | - Sylvain Jaffuel
- Department of Infectious Diseases, Brest University Hospital, Brest, France
| | - Francis Couturaud
- Department of Internal Medicine and Pneumology, Brest University Hospital, Brest, France; University of Brest, EA3878 (GETBO), CIC INSERM 0502, SFR 148, Brest, France
| | - Aurélien Delluc
- Department of Internal Medicine and Pneumology, Brest University Hospital, Brest, France; University of Brest, EA3878 (GETBO), CIC INSERM 0502, SFR 148, Brest, France
| | | | | | - Yann Le Meur
- Department of Nephrology and Renal Transplantation Unit, Brest University Hospital, Brest, France; University of Brest, EA 2216, SFR 148, Brest, France
| | | | - Anne Totet
- University of Picardy-Jules Verne, UMR-I 01, SFR Cap Santé, Amiens, France; Laboratory of Parasitology and Mycology, Amiens University Hospital, Amiens, France
| | - Jean Menotti
- Laboratory of Parasitology and Mycology, Saint Louis Hospital APHP, Paris, France; Paris-Diderot University, Paris, France
| | - Gilles Nevez
- University of Brest, LUBEM EA 3882, SFR 148, Brest, France; Laboratory of Parasitology and Mycology, Brest University Hospital, Brest, France.
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Abstract
Since its initial misidentification as a trypanosome some 100 years ago, Pneumocystis has remained recalcitrant to study. Although we have learned much, we still do not have definitive answers to such basic questions as, where is the reservoir of infection, how does Pneumocystis reproduce, what is the mechanism of infection, and are there true species of Pneumocystis? The goal of this review is to provide the reader the most up to date information available about the biology of Pneumocystis and the disease it produces.
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Affiliation(s)
- Francis Gigliotti
- Department of Pediatrics, University of Rochester Medical School, Rochester, New York 14642
| | - Andrew H Limper
- Pulmonary and Critical Care Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota 55905
| | - Terry Wright
- Department of Pediatrics, University of Rochester Medical School, Rochester, New York 14642
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Diagnosis of Pneumocystis jirovecii Pneumonia: Role of β-D-Glucan Detection and PCR. CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-014-0198-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Kim HS, DO SI, Kim YW. Histopathology of Pneumocystis carinii pneumonia in immunocompetent laboratory rats. Exp Ther Med 2014; 8:442-446. [PMID: 25009598 PMCID: PMC4079405 DOI: 10.3892/etm.2014.1732] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 04/29/2014] [Indexed: 11/23/2022] Open
Abstract
The occurrence of idiopathic pulmonary lesions in laboratory rats, characterized by lymphohistiocytic interstitial pneumonia with dense perivascular lymphoid cuffs, has been reported over the past decade. Although the term rat respiratory virus (RRV) was adopted to confer a putative viral etiology to the idiopathic pulmonary lesions, the etiology of this disease remains to be elucidated. Recently, inflammatory lesions have been observed in the lungs of immunocompetent laboratory rats similar to those previously described. Based on the latest evidence indicating that Pneumocystis carinii (P. carinii), and not putative RRV, causes infectious interstitial pneumonia in laboratory rats, the present study investigated whether the pulmonary lesions observed were caused by P. carinii infection. Male Sprague-Dawley rats, free of known pathogens, were introduced into a rat colony positive for RRV-type lesions. Routine histopathological examinations were performed on the rat lung tissues following exposure. The presence of Pneumocystis organisms was confirmed using Grocott’s methenamine silver (GMS) staining. At week 3 following introduction, a few small lymphoid aggregates were located adjacent to the edematous vascular sheath. By week 5, foci of dense perivascular lymphoid cuffing were observed. Multifocal lymphohistiocytic interstitial pneumonia and prominent lymphoid perivascular cuffs were observed between week 7 and 10. GMS staining confirmed the presence of Pneumocystis cysts. Thus, the results of the present study demonstrated that P. carinii caused lymphohistiocytic interstitial pneumonia in a group of laboratory rats. The observations strongly support the conclusion that P. carinii infection in immunocompetent laboratory rats causes the lung lesions that were previously attributed to RRV.
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Affiliation(s)
- Hyun-Soo Kim
- Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Republic of Korea ; Republic of Korea Air Force Aerospace Medical Center, Chungcheongbuk-do 363-849, Republic of Korea
| | - Sung-Im DO
- Department of Pathology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Youn Wha Kim
- Department of Pathology, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
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Ripamonti C, Bishop LR, Yang J, Lempicki RA, Kovacs JA. Clearance of Pneumocystis murina infection is not dependent on MyD88. Microbes Infect 2014; 16:522-7. [PMID: 24680862 PMCID: PMC4071138 DOI: 10.1016/j.micinf.2014.03.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/26/2014] [Accepted: 03/10/2014] [Indexed: 11/20/2022]
Abstract
To determine if myeloid differentiation factor 88 (MyD88), which is necessary for signaling by most TLRs and IL-1Rs, is necessary for control of Pneumocystis infection, MyD88-deficient and wild-type mice were infected with Pneumocystis by exposure to infected seeder mice and were followed for up to 106 days. MyD88-deficient mice showed clearance of Pneumocystis and development of anti-Pneumocystis antibody responses with kinetics similar to wild-type mice. Based on expression levels of select genes, MyD88-deficient mice developed immune responses similar to wild-type mice. Thus, MyD88 and the upstream pathways that rely on MyD88 signaling are not required for control of Pneumocystis infection.
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Affiliation(s)
- Chiara Ripamonti
- Critical Care Medicine Department, NIH Clinical Center, NIH, Building 10, Room 2C145, MSC 1662, Bethesda, MD 20892-1662, USA
| | - Lisa R Bishop
- Critical Care Medicine Department, NIH Clinical Center, NIH, Building 10, Room 2C145, MSC 1662, Bethesda, MD 20892-1662, USA
| | - Jun Yang
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Richard A Lempicki
- Laboratory of Immunopathogenesis and Bioinformatics, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Joseph A Kovacs
- Critical Care Medicine Department, NIH Clinical Center, NIH, Building 10, Room 2C145, MSC 1662, Bethesda, MD 20892-1662, USA.
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27
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Multilocus microsatellite genotyping array for investigation of genetic epidemiology of Pneumocystis jirovecii. J Clin Microbiol 2014; 52:1391-9. [PMID: 24523468 DOI: 10.1128/jcm.02531-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pneumocystis jirovecii is a symbiotic respiratory fungus that causes pneumonia (PcP) in immunosuppressed patients. Because P. jirovecii cannot be reliably cultured in vitro, it has proven difficult to study and gaps in our understanding of the organism persist. The release of a draft genome for the organism opens the door for the development of new genotyping approaches for studying its molecular epidemiology and global population structure. We identified and validated 8 putatively neutral microsatellite markers and 1 microsatellite marker linked to the dihydropteroate synthase gene (dhps), the enzymatic target of sulfa drugs used for PcP prevention and treatment. Using these tools, we analyzed P. jirovecii isolates from HIV-infected patients from three geographically distant populations: Uganda, the United States, and Spain. Among the 8 neutral markers, we observed high levels of allelic heterozygosity (average He, 0.586 to 0.842). Consistent with past reports, we observed limited global population structuring, with only the Ugandan isolates showing minor differentiation from the other two populations. In Ugandan isolates that harbored mutations in dhps, the microsatellite locus linked to dhps demonstrated a depressed He, consistent with positive directional selection for sulfa resistance mutations. Using a subset of these microsatellites, analyses of individual and paired samples from infections in San Francisco, CA, showed reliable typeability within a single infection and high discriminatory power between infections. These features suggest that this novel microsatellite typing approach will be an effective tool for molecular-epidemiological investigations into P. jirovecii population structure, transmission, and drug resistance.
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28
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Martinez A, Halliez MCM, Aliouat EM, Chabé M, Standaert-Vitse A, Fréalle E, Gantois N, Pottier M, Pinon A, Dei-Cas E, Aliouat-Denis CM. Growth and airborne transmission of cell-sorted life cycle stages of Pneumocystis carinii. PLoS One 2013; 8:e79958. [PMID: 24223207 PMCID: PMC3819301 DOI: 10.1371/journal.pone.0079958] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 09/30/2013] [Indexed: 01/15/2023] Open
Abstract
Pneumocystis organisms are airborne opportunistic pathogens that cannot be continuously grown in culture. Consequently, the follow-up of Pneumocystis stage-to-stage differentiation, the sequence of their multiplication processes as well as formal identification of the transmitted form have remained elusive. The successful high-speed cell sorting of trophic and cystic forms is paving the way for the elucidation of the complex Pneumocystis life cycle. The growth of each sorted Pneumocystis stage population was followed up independently both in nude rats and in vitro. In addition, by setting up a novel nude rat model, we attempted to delineate which cystic and/or trophic forms can be naturally aerially transmitted from host to host. The results showed that in axenic culture, cystic forms can differentiate into trophic forms, whereas trophic forms are unable to evolve into cystic forms. In contrast, nude rats inoculated with pure trophic forms are able to produce cystic forms and vice versa. Transmission experiments indicated that 12 h of contact between seeder and recipient nude rats was sufficient for cystic forms to be aerially transmitted. In conclusion, trophic- to cystic-form transition is a key step in the proliferation of Pneumocystis microfungi because the cystic forms (but not the trophic forms) can be transmitted by aerial route from host to host.
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Affiliation(s)
- Anna Martinez
- Biology and Diversity of Emerging Eukaryotic Pathogens (BDEEP), Center for Infection and Immunity of Lille (CIIL), INSERM U1019, CNRS UMR 8204, EA-4547, Univ Lille Nord de France, Institut Pasteur de Lille, Lille, France ; Japan Collection of Microorganisms, RIKEN BioResource Center, Koyadai, Tsukuba, Ibaraki, Japan
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29
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Siberry GK, Abzug MJ, Nachman S, Brady MT, Dominguez KL, Handelsman E, Mofenson LM, Nesheim S, National Institutes of Health, Centers for Disease Control and Prevention, HIV Medicine Association of the Infectious Diseases Society of America, Pediatric Infectious Diseases Society, American Academy of Pediatrics. Guidelines for the prevention and treatment of opportunistic infections in HIV-exposed and HIV-infected children: recommendations from the National Institutes of Health, Centers for Disease Control and Prevention, the HIV Medicine Association of the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the American Academy of Pediatrics. Pediatr Infect Dis J 2013; 32 Suppl 2:i-KK4. [PMID: 24569199 PMCID: PMC4169043 DOI: 10.1097/01.inf.0000437856.09540.11] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- George K Siberry
- 1National Institutes of Health, Bethesda, Maryland 2University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado 3State University of New York at Stony Brook, Stony Brook, New York 4Nationwide Children's Hospital, Columbus, Ohio 5Centers for Disease Control and Prevention, Atlanta, Georgia
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30
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Combined quantification of pulmonary Pneumocystis jirovecii DNA and serum (1->3)-β-D-glucan for differential diagnosis of pneumocystis pneumonia and Pneumocystis colonization. J Clin Microbiol 2013; 51:3380-8. [PMID: 23903553 DOI: 10.1128/jcm.01554-13] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study assessed a quantitative PCR (qPCR) assay for Pneumocystis jirovecii quantification in bronchoalveolar lavage (BAL) fluid samples combined with serum (1→3)-β-d-glucan (BG) level detection to distinguish Pneumocystis pneumonia (PCP) from pulmonary colonization with P. jirovecii. Forty-six patients for whom P. jirovecii was initially detected in BAL fluid samples were retrospectively enrolled. Based on clinical data and results of P. jirovecii detection, 17 and 29 patients were diagnosed with PCP and colonization, respectively. BAL fluid samples were reassayed using a qPCR assay targeting the mitochondrial large subunit rRNA gene. qPCR results and serum BG levels (from a Fungitell kit) were analyzed conjointly. P. jirovecii DNA copy numbers were significantly higher in the PCP group than in the colonization group (1.3 × 10(7) versus 3.4 × 10(3) copies/μl, P < 0.05). A lower cutoff value (1.6 × 10(3) copies/μl) achieving 100% sensitivity for PCP diagnosis and an upper cutoff value (2 × 10(4) copies/μl) achieving 100% specificity were determined. Applying these two values, 13/17 PCP patients and 19/29 colonized patients were correctly assigned to their patient groups. For the remaining 14 patients with P. jirovecii DNA copy numbers between the cutoff values, PCP and colonization could not be distinguished on the basis of qPCR results. Four of these patients who were initially assigned to the PCP group presented BG levels of ≥100 pg/ml. The other 10 patients, who were initially assigned to the colonization group, presented BG levels of <100 pg/ml. These results suggest that the combination of the qPCR assay, applying cutoff values of 1.6 × 10(3) and 2 × 10(4) copies/μl, and serum BG detection, applying a 100 pg/ml threshold, can differentiate PCP and colonization diagnoses.
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31
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Menotti J, Emmanuel A, Bouchekouk C, Chabe M, Choukri F, Pottier M, Sarfati C, Aliouat EM, Derouin F. Evidence of airborne excretion of Pneumocystis carinii during infection in immunocompetent rats. Lung involvement and antibody response. PLoS One 2013; 8:e62155. [PMID: 23626781 PMCID: PMC3633925 DOI: 10.1371/journal.pone.0062155] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 03/18/2013] [Indexed: 01/15/2023] Open
Abstract
To better understand the role of immunocompetent hosts in the diffusion of Pneumocystis in the environment, airborne shedding of Pneumocystis carinii in the surrounding air of experimentally infected Sprague Dawley rats was quantified by means of a real-time PCR assay, in parallel with the kinetics of P. carinii loads in lungs and specific serum antibody titres. Pneumocystis-free Sprague Dawley rats were intratracheally inoculated at day 0 (d0) and then followed for 60 days. P. carinii DNA was detected in lungs until d29 in two separate experiments and thereafter remained undetectable. A transient air excretion of Pneumocystis DNA was observed between d14 and d22 in the first experiment and between d9 and d19 in the second experiment; it was related to the peak of infection in lungs. IgM and IgG anti-P. carinii antibody increase preceded clearance of P. carinii in the lungs and cessation of airborne excretion. In rats receiving a second challenge 3 months after the first inoculation, Pneumocystis was only detected at a low level in the lungs of 2 of 3 rats at d2 post challenge and was never detected in air samples. Anti-Pneumocystis antibody determinations showed a typical secondary IgG antibody response. This study provides the first direct evidence that immunocompetent hosts can excrete Pneumocystis following a primary acquired infection. Lung infection was apparently controlled by the immune response since fungal burdens decreased to become undetectable as specific antibodies reached high titres in serum. This immune response was apparently protective against reinfection 3 months later.
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Affiliation(s)
- Jean Menotti
- Department of Parasitology-Mycology, E.A.3520, Paris-Diderot University, Sorbonne Paris Cité and Saint-Louis Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.
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32
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Dimonte S, Berrilli F, D’Orazi C, D’Alfonso R, Placco F, Bordi E, Perno C, Di Cave D. Molecular analysis based on mtLSU-rRNA and DHPS sequences of Pneumocystis jirovecii from immunocompromised and immunocompetent patients in Italy. INFECTION GENETICS AND EVOLUTION 2013. [DOI: 10.1016/j.meegid.2012.11.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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33
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Affiliation(s)
- Francis Gigliotti
- Division of Pediatric Infectious Diseases, Department of Pediatrics, University of Rochester School of Medicine, Rochester, New York, United States of America.
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34
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Characterizing Pneumocystis in the lungs of bats: understanding Pneumocystis evolution and the spread of Pneumocystis organisms in mammal populations. Appl Environ Microbiol 2012; 78:8122-36. [PMID: 23001662 DOI: 10.1128/aem.01791-12] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bats belong to a wide variety of species and occupy diversified habitats, from cities to the countryside. Their different diets (i.e., nectarivore, frugivore, insectivore, hematophage) lead Chiroptera to colonize a range of ecological niches. These flying mammals exert an undisputable impact on both ecosystems and circulation of pathogens that they harbor. Pneumocystis species are recognized as major opportunistic fungal pathogens which cause life-threatening pneumonia in severely immunocompromised or weakened mammals. Pneumocystis consists of a heterogeneous group of highly adapted host-specific fungal parasites that colonize a wide range of mammalian hosts. In the present study, 216 lungs of 19 bat species, sampled from diverse biotopes in the New and Old Worlds, were examined. Each bat species may be harboring a specific Pneumocystis species. We report 32.9% of Pneumocystis carriage in wild bats (41.9% in Microchiroptera). Ecological and behavioral factors (elevation, crowding, migration) seemed to influence the Pneumocystis carriage. This study suggests that Pneumocystis-host association may yield much information on Pneumocystis transmission, phylogeny, and biology in mammals. Moreover, the link between genetic variability of Pneumocystis isolated from populations of the same bat species and their geographic area could be exploited in terms of phylogeography.
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Abstract
Although the incidence of Pneumocystis pneumonia (PCP) has decreased since the introduction of combination antiretroviral therapy, it remains an important cause of disease in both HIV-infected and non-HIV-infected immunosuppressed populations. The epidemiology of PCP has shifted over the course of the HIV epidemic both from changes in HIV and PCP treatment and prevention and from changes in critical care medicine. Although less common in non-HIV-infected immunosuppressed patients, PCP is now more frequently seen due to the increasing numbers of organ transplants and development of novel immunotherapies. New diagnostic and treatment modalities are under investigation. The immune response is critical in preventing this disease but also results in lung damage, and future work may offer potential areas for vaccine development or immunomodulatory therapy. Colonization with Pneumocystis is an area of increasing clinical and research interest and may be important in development of lung diseases such as chronic obstructive pulmonary disease. In this review, we discuss current clinical and research topics in the study of Pneumocystis and highlight areas for future research.
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36
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Henderson KS, Dole V, Parker NJ, Momtsios P, Banu L, Brouillette R, Simon MA, Albers TM, Pritchett-Corning KR, Clifford CB, Shek WR. Pneumocystis carinii causes a distinctive interstitial pneumonia in immunocompetent laboratory rats that had been attributed to "rat respiratory virus". Vet Pathol 2012; 49:440-52. [PMID: 22308234 DOI: 10.1177/0300985811432351] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A prevalent and distinctive infectious interstitial pneumonia (IIP) of immunocompetent laboratory rats was suspected to be caused by a putative virus, termed rat respiratory virus, but this was never substantiated. To study this disease, 2 isolators were independently populated with rats from colonies with endemic disease, which was perpetuated by the regular addition of naive rats. After Pneumocystis was demonstrated by histopathology and polymerase chain reaction (PCR) in the lungs of rats from both isolators and an earlier bedding transmission study, the relationship between Pneumocystis and IIP was explored further by analyzing specimens from 3 contact transmission experiments, diagnostic submissions, and barrier room breeding colonies, including 1 with and 49 without IIP. Quantitative (q) PCR and immunofluorescence assay only detected Pneumocystis infection and serum antibodies in rats from experiments or colonies in which IIP was diagnosed by histopathology. In immunocompetent hosts, the Pneumocystis concentration in lungs corresponded to the severity and prevalence of IIP; seroconversion occurred when IIP developed and was followed by the concurrent clearance of Pneumocystis from lungs and resolution of disease. Experimentally infected immunodeficient RNU rats, by contrast, did not seroconvert to Pneumocystis or recover from infection. qPCR found Pneumocystis at significantly higher concentrations and much more often in lungs than in bronchial and nasal washes and failed to detect Pneumocystis in oral swabs. The sequences of a mitochondrial ribosomal large-subunit gene region for Pneumocystis from 11 distinct IIP sources were all identical to that of P. carinii. These data provide substantial evidence that P. carinii causes IIP in immunocompetent rats.
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Affiliation(s)
- K S Henderson
- Research Models and Services, Charles River, 251 Ballardvale St, Wilmington, MA 01887, USA.
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Choukri F, Aliouat EM, Menotti J, Totet A, Gantois N, Garin YJF, Bergeron V, Dei-cas E, Derouin F. Dynamics of Pneumocystis carinii Air Shedding During Experimental Pneumocystosis. J Infect Dis 2011; 203:1333-6. [DOI: 10.1093/infdis/jir018] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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38
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Mekinian A, Durand-Joly I, Hatron PY, Moranne O, Denis G, Dei-Cas E, Morell-Dubois S, Lambert M, Launay D, Delhaes L, Hachulla E, Queyrel V. Pneumocystis jirovecii colonization in patients with systemic autoimmune diseases: prevalence, risk factors of colonization and outcome. Rheumatology (Oxford) 2010; 50:569-77. [DOI: 10.1093/rheumatology/keq314] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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39
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Pneumocystis Jirovecii Pneumonia: Current Knowledge and Outstanding Public Health Issues. CURRENT FUNGAL INFECTION REPORTS 2010. [DOI: 10.1007/s12281-010-0029-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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40
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Catherinot E, Lanternier F, Bougnoux ME, Lecuit M, Couderc LJ, Lortholary O. Pneumocystis jirovecii Pneumonia. Infect Dis Clin North Am 2010; 24:107-38. [PMID: 20171548 DOI: 10.1016/j.idc.2009.10.010] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Pneumocystis jirovecii has gained attention during the last decade in the context of the AIDS epidemic and the increasing use of cytotoxic and immunosuppressive therapies. This article summarizes current knowledge on biology, pathophysiology, epidemiology, diagnosis, prevention, and treatment of pulmonary P jirovecii infection, with a particular focus on the evolving pathophysiology and epidemiology. Pneumocystis pneumonia still remains a severe opportunistic infection, associated with a high mortality rate.
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Affiliation(s)
- Emilie Catherinot
- Université Paris Descartes, Service de Maladies Infectieuses et Tropicales, 149 Rue de Sèvres, Centre d'Infectiologie Necker-Pasteur, Hôpital Necker-Enfants Malades, Paris 75015, France
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41
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Castro JG, Morrison-Bryant M. Management of Pneumocystis Jirovecii pneumonia in HIV infected patients: current options, challenges and future directions. HIV AIDS-RESEARCH AND PALLIATIVE CARE 2010; 2:123-34. [PMID: 22096390 PMCID: PMC3218692 DOI: 10.2147/hiv.s7720] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The discovery of the Human Immunodeficiency Virus (HIV) was led by the merge of clustered cases of Pneumocystis jirovecii Pneumonia (PCP) in otherwise healthy people in the early 80’s.1,2 In the face of sophisticated treatment now available for HIV infection, life expectancy approaches normal limits. It has dramatically changed the natural course of HIV from a nearly fatal infection to a chronic disease.3–5 However, PCP still remains a relatively common presentation of uncontrolled HIV. Despite the knowledge and advances gained in the prevention and management of PCP infection, it continues to have high morbidity and mortality rates. Trimethoprim-sulfamethoxazole (TMP-SMZ) remains as the recommended first-line treatment. Alternatives include pentamidine, dapsone plus trimethoprim, clindamycin administered with primaquine, and atovaquone. For optimal management, clinicians need to be familiar with the advantages and disadvantages of the available drugs. The parameters used to classify severity of infection are also important, as it is well known that the adjunctive use of steroids in moderate to severe cases have been shown to significantly improve outcome. Evolving management practices, such as the successful institution of early antiretroviral therapy, may further enhance overall survival rates.
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Affiliation(s)
- Jose G Castro
- Division of Infectious Diseases, University of Miami Miller School of Medicine, Miami, Florida, USA
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42
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Chabé M, Nevez G, Totet A, Fréalle E, Delhaes L, Aliouat E, Dei-Cas E. Transmission de Pneumocystis. J Mycol Med 2009. [DOI: 10.1016/j.mycmed.2009.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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43
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Kling HM, Shipley TW, Patil S, Morris A, Norris KA. Pneumocystis colonization in immunocompetent and simian immunodeficiency virus-infected cynomolgus macaques. J Infect Dis 2009; 199:89-96. [PMID: 19014344 DOI: 10.1086/595297] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Pneumocystis (Pc) colonization is common among human immunodeficiency virus (HIV)-infected subjects, although the clinical consequences of Pc carriage are not fully understood. We examined the frequency of asymptomatic carriage in healthy and simian immunodeficiency virus (SIV)-infected cynomolgus macaques by use of polymerase chain reaction (PCR) and assessment of changes in the serologic response to a recombinant fragment of the Pc protein kexin (KEX1). Anti-KEX1 antibodies were detected in 95% of healthy monkeys. To create a model of natural transmission of Pc, SIV-infected monkeys were cohoused with macaques coinfected with SIV and Pc. Pc colonization occurred when the CD4(+) T cell count decreased to <500 cells/microL, despite anti-Pc prophylaxis with trimethoprim-sulfamethoxazole. Increases in anti-KEX1 antibody titers preceded detection of Pc DNA in bronchoalveolar lavage (BAL) fluid samples by use of PCR. These results demonstrate the usefulness of recombinant KEX1 in serologic studies of Pc colonization and will improve the understanding of Pc transmission and clinical consequences of Pc colonization in HIV-infected patients.
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Affiliation(s)
- Heather M Kling
- Department of Immunology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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Linke MJ, Ashbaugh AD, Demland JA, Walzer PD. Pneumocystis murina colonization in immunocompetent surfactant protein A deficient mice following environmental exposure. Respir Res 2009; 10:10. [PMID: 19228388 PMCID: PMC2650685 DOI: 10.1186/1465-9921-10-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 02/19/2009] [Indexed: 12/19/2022] Open
Abstract
Background Pneumocystis spp. are opportunistic pathogens that cause pneumonia in immunocompromised humans and animals. Pneumocystis colonization has also been detected in immunocompetent hosts and may exacerbate other pulmonary diseases. Surfactant protein A (SP-A) is an innate host defense molecule and plays a role in the host response to Pneumocystis. Methods To analyze the role of SP-A in protecting the immunocompetent host from Pneumocystis colonization, the susceptibility of immunocompetent mice deficient in SP-A (KO) and wild-type (WT) mice to P. murina colonization was analyzed by reverse-transcriptase quantitative PCR (qPCR) and serum antibodies were measured by enzyme-linked immunosorbent assay (ELISA). Results Detection of P. murina specific serum antibodies in immunocompetent WT and KO mice indicated that the both strains of mice had been exposed to P. murina within the animal facility. However, P. murina mRNA was only detected by qPCR in the lungs of the KO mice. The incidence and level of the mRNA expression peaked at 8–10 weeks and declined to undetectable levels by 16–18 weeks. When the mice were immunosuppressed, P. murina cyst forms were also only detected in KO mice. P. murina mRNA was detected in SCID mice that had been exposed to KO mice, demonstrating that the immunocompetent KO mice are capable of transmitting the infection to immunodeficient mice. The pulmonary cellular response appeared to be responsible for the clearance of the colonization. More CD4+ and CD8+ T-cells were recovered from the lungs of immunocompetent KO mice than from WT mice, and the colonization in KO mice depleted CD4+ cells was not cleared. Conclusion These data support an important role for SP-A in protecting the immunocompetent host from P. murina colonization, and provide a model to study Pneumocystis colonization acquired via environmental exposure in humans. The results also illustrate the difficulties in keeping mice from exposure to P. murina even when housed under barrier conditions.
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Affiliation(s)
- Michael J Linke
- Research Service, Veterans Affairs Medical Center, Cincinnati, OH, USA.
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Aliouat-Denis CM, Chabé M, Demanche C, Aliouat EM, Viscogliosi E, Guillot J, Delhaes L, Dei-Cas E. Pneumocystis species, co-evolution and pathogenic power. INFECTION GENETICS AND EVOLUTION 2008; 8:708-26. [DOI: 10.1016/j.meegid.2008.05.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 05/02/2008] [Accepted: 05/03/2008] [Indexed: 01/13/2023]
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Wiley JA, Harmsen AG. Pneumocystis infection enhances antibody-mediated resistance to a subsequent influenza infection. THE JOURNAL OF IMMUNOLOGY 2008; 180:5613-24. [PMID: 18390746 DOI: 10.4049/jimmunol.180.8.5613] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In contrast to the detrimental outcomes most often associated with the resolution of coinfections, the model presented here involving a localized Pneumocystis infection of the lung, followed 2 wk later by an influenza virus infection, results in a significant beneficial outcome for the host. In the week following the influenza infection, immunocompetent coinfected animals exhibited an accelerated rate of virus clearance, an accelerated appearance of higher influenza-specific neutralizing Ab titers in their serum and bronchoalveolar lavage fluid (BALF), significantly reduced inflammatory cytokine levels in their BALF, and reduced levels of morbidity relative to animals infected only with influenza virus. The beneficial outcome observed in coinfected immunocompetent animals was dependent on the ongoing resolution of a viable Pneumocystis infection. No differences in viral clearance were detected between coinfected and influenza-only-infected muMT mice or likewise for SCID mice. The accelerated anti-influenza response did not appear to be associated with influenza-specific CD8 T cell-mediated responses or NK cell responses in the lung. Rather, the increased rate of viral clearance was due to the enhancement of the influenza-specific Ab response, which in turn was transiently dependent upon the resolution of the ongoing Pneumocystis infection.
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Affiliation(s)
- James A Wiley
- Department of Veterinary Molecular Biology, Montana State University, Bozeman, MT 59715, USA.
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Spencer L, Ukwu M, Alexander T, Valadez K, Liu L, Frederick T, Kovacs A, Morris A. Epidemiology of Pneumocystis colonization in families. Clin Infect Dis 2008; 46:1237-40. [PMID: 18444861 PMCID: PMC2613645 DOI: 10.1086/533449] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Whether Pneumocystis colonization is transmitted in families with human immunodeficiency virus (HIV)-infected members is unknown. Using nested polymerase chain reaction of oropharyngeal or nasopharyngeal samples, we detected colonization in 11.4% of HIV-infected adults and in 3.3% of their children, but there was no evidence of clustering.
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Affiliation(s)
- LaShonda Spencer
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Michelle Ukwu
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
| | - Travis Alexander
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
| | - Karri Valadez
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
| | - Lora Liu
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Toni Frederick
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Andrea Kovacs
- Maternal Child and Adolescent Center for Infectious Diseases and Virology, University of Southern California, Los Angeles, CA, United States
| | - Alison Morris
- Department of Medicine, Division of Pulmonary and Critical Care Medicine and the Will Rogers Institute Pulmonary Research Center, University of Southern California, Los Angeles, CA, United States
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Abstract
Chronic obstructive pulmonary disease (COPD) results in significant morbidity and mortality. Smoking has long been recognized as the primary risk factor for development of COPD, but factors determining the severity or pattern of disease in smokers are largely unknown. Recent interest has focused on the potential role of infectious agents and the associated host response in accelerating progression of airway obstruction or in perpetuating its progression following discontinuation of tobacco exposure. Pneumocystis jirovecii is a fungal pathogen that causes pneumonia in immunocompromised individuals. Recent evidence has linked this organism with COPD. Using sensitive molecular techniques, low levels of Pneumocystis have been detected in the respiratory tract of certain individuals and termed colonization. Several findings support the theory that colonization with Pneumocystis is involved in the "vicious circle" hypothesis of COPD in which colonization with organisms perpetuates an inflammatory and lung remodeling response. Pneumocystis colonization is more prevalent in smokers and in those with severe COPD. The presence of Pneumocystis in the lungs, even at low levels, produces inflammatory changes similar to those seen in COPD, with increases in numbers of neutrophils and CD8(+) lymphocytes. HIV-infected subjects who have had PCP develop permanent airway obstruction, and HIV-infected patients have a high prevalence of both emphysema and Pneumocystis colonization. In addition, a non-human primate model of colonization shows development of airway obstruction and radiographic emphysema. Additional studies are needed to confirm the role of Pneumocystis in the pathogenesis of COPD, given that this agent might be a treatable co-factor in disease progression.
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Affiliation(s)
- Alison Morris
- Division of Pulmonary, Allergy, and Critical Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Morris A, Wei K, Afshar K, Huang L. Epidemiology and Clinical Significance ofPneumocystisColonization. J Infect Dis 2008; 197:10-7. [DOI: 10.1086/523814] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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Hollifield M, Bou Ghanem E, de Villiers WJS, Garvy BA. Scavenger receptor A dampens induction of inflammation in response to the fungal pathogen Pneumocystis carinii. Infect Immun 2007; 75:3999-4005. [PMID: 17548480 PMCID: PMC1951997 DOI: 10.1128/iai.00393-07] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alveolar macrophages are the effector cells largely responsible for clearance of Pneumocystis carinii from the lungs. Binding of organisms to beta-glucan and mannose receptors has been shown to stimulate phagocytosis of the organisms. To further define the mechanisms used by alveolar macrophages for clearance of P. carinii, mice deficient in the expression of scavenger receptor A (SRA) were infected with P. carinii, and clearance of organisms was monitored over time. SRA-deficient (SRAKO) mice consistently cleared P. carinii faster than did wild-type control mice. Expedited clearance corresponded to elevated numbers of activated CD4(+) T cells in the alveolar spaces of SRAKO mice compared to wild-type mice. Alveolar macrophages from SRAKO mice had increased expression of CD11b on their surfaces, consistent with an activated phenotype. However, they were not more phagocytic than macrophages expressing SRA, as measured by an in vivo phagocytosis assay. SRAKO alveolar macrophages produced significantly more tumor necrosis factor alpha (TNF-alpha) than wild-type macrophages when stimulated with lipopolysaccharide in vitro but less TNF-alpha in response to P. carinii in vitro. However, upon in vivo stimulation, SRAKO mice produced significantly more TNF-alpha, interleukin 12 (IL-12), and IL-18 in response to P. carinii infection than did wild-type mice. Together, these data indicate that SRA controls inflammatory cytokines produced by alveolar macrophages in the context of P. carinii infection.
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Affiliation(s)
- Melissa Hollifield
- University of Kentucky Chandler Medical Center, 800 Rose Street, Lexington, KY 40536-0298, USA
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